The invention is directed to solenoid valves, and more particularly to a solenoid valve incorporating an improved check valve.
A solenoid valve of the type with which this invention is concerned is disclosed in DE 196 35 693 A1, and in which the check valve has a ball-shaped closing body made of steel, which is associated with a hollow conical valve seat in a valve component. Since the valve component is injection molded of thermoplastic synthetic resin or plastic material and has a non-uniform mass distribution, dimensional deviations of the valve seat occur during manufacture and during insertion with the solenoid valve into a housing of a hydraulic unit of a slip-controlled hydraulic brake system of a motor vehicle and these dimensional deviations, in combination with the dimensionally stable closing body, lead to leakage problems in the check valve at low pressures.
The solenoid valve according to the invention has the advantage over the prior art that even at low pressures in the check valve, the sealing function of the rubber-elastic sealing ring is effective, but at higher pressures, the dimensionally stable closing body protects the sealing ring from being overloaded and damaged by virtue of the fact that the closing body reduces the gap in relation to the valve seat and therefore largely prevents an extrusion of the rubber-elastic sealing ring into the gap. As a result, on the one hand, the disadvantages of the known solenoid valves are overcome and on the other hand, difficulties in sealing at high pressure due to the relatively soft sealing ring are prevented in a simple manner.